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  1. S

    Is the real world deterministic?

    Good point. Well, our brain is very complex, but in the case of determinism (as you mentioned by knowing the exact initial states of all the matter) our brain would always decide the same. Also you mentioned a very interesting thing about the spontaneous decay. My quick argument is that: we...
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    Is the real world deterministic?

    Well, I would say there IS an imaginary experiment. And that is to prepare two absolutely identical systems which are known to have a random nature and monitor their evolution. The two systems should be the same in an infinite accuracy. I am not sure if it is possible! but it is the simplest plan.
  3. S

    Is the real world deterministic?

    Could you please explain this more? Is there any work done on this by a physicist? (Actually I do physics and I'm not a philosopher!) Thanks.
  4. S

    Is the real world deterministic?

    Do you know of any theory or evidence that shows the real world is (or is not) deterministic? By "deterministic" I mean: If we give exactly the same initial conditions to any system in the world, does it evolve to the same state?
  5. S

    Bound states and Current density

    The current density vanishes for a bound state. I would like to know the proof and its physical significance. I appreciate the responses in advance!
  6. S

    Energy unit

    I have seen in text that it used an unfamiliar unit for fine-structure energy difference in a species. The unit was: cm^-1. I need these energies to do some statistical calculations in exp(-beta*E). Can anyone tell me how can I convert this unit or convert beta to this unit? Thanks!
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    Constraints in Hamilton's equations

    Dear Shooting star, Thanks for writing. But I'm looking for some techniqe jist similar to one we use in Lagrangian viewpoint as undetermined constants and the way we treat with constraint equations there.
  8. S

    Constraints in Hamilton's equations

    My question is about the constraints in Hamiltonian viewpoint. I mean, where the constraints are put into the Hamilton's equations. Constraints are usually studied in Lagrange's equations in text books (such as Jose and Goldstein). However, I couldn't find anything about constraints in...
  9. S

    The angle between two 3D lines

    Thank you. I'll try it!!!
  10. S

    The angle between two 3D lines

    Can anyone tell me how can I calculate the angle between two lines in 3D. I need in my codings. I know it has a simple solution. but I really have mixed up!!! Thanks.
  11. S

    Statistical physics

    I read a book named :Statistical Mechanics:An Introduction; by Trevena. I really enjoyed the approch of it. It had some really interesting approches to build the distributions. I really advise it. But not as the complete book you need!!! Somy:smile:
  12. S

    How to time a circuit

    Well there is a time delay in any electronic device!!! Let me ask you another question. Why you need to know that time lag???
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    How to time a circuit

    there are some theoretical ways to time this delay. You can see it in details in any books relating to the control sciences. But I'm affraid about the existance of any experimental method (because of the your accuracy limits). Anyway, Good Luck!!! Somy
  14. S

    News Gaming an Iran contingency

    well, as an Iranian!, and a person who was working on a research project in Atomic Energy Organization of Iran, I believe that there is no atomic weapon production in Iran. everything is just peaceful. Many people in Iran believe that, it is just a scenario from USA. In fact, they want to do...
  15. S

    Information on the percolation threshold

    Hi. I can introduce you a useful book: Physics and Geometry of Disorder. by A. Efros. U can find very useful information about percolation theory. Good Luck. Somy:smile:
  16. S

    Statistical physics

    Hi. I need some useful and conceptual book in advanced statistical physics. I can understand the mathematics in some famous book such as Pathria, but I have trouble understanding some concepts in that area. Any suggestion?!!! Thanks in advance. Somy
  17. S

    PF is taken over by space robots?

    I think the colors used is very boring. just like a cloudy weather with snow. Not very interesting for me!!!
  18. S

    PF is taken over by space robots?

    *****ing???!!!
  19. S

    PF is taken over by space robots?

    New LOGO!!! Hi. I really have problem with this new logo of PF. I believe the past appearance was much more better. Do you think so???
  20. S

    A question on group theory

    I think so. Thanks dear Careful!
  21. S

    A question on group theory

    Hi all. I'm studying Wybourne book on group theory. I didn't understand this expression: U(p,q) I know what U(p+q,C) and U(n) means, but I'm unfamiliar with the notation of the above statement. Thanks in advance. Somy:smile:
  22. S

    Heisenberg Hamiltonian

    but I thout it was related to solid state of matter. the hamiltonian of the linking energies. yes???
  23. S

    Heisenberg Hamiltonian

    Hi. Can anyone tell me what exactly the "Heisenberg Hamiltonian" is??? I found it in an article related to: the renormalization group. Thanks in advance. Somy:smile:
  24. S

    An emergency question

    ok!!! I just wanted to get an idea about it. I'll try it for myself. Thank you
  25. S

    An emergency question

    an emergency question!!! Hi all. I just wanted the proof of this statement via group theory: det(AB)=det(A)det(B) thanks in advance. somy:smile:
  26. S

    Action at a distance

    Hi all. I want to know what do they mean by "action at distance". I know the concept of field(!!!) and the meaning of "space geometry effects". I wanted to know something about the history of this concept. Thank you. Somy :smile:
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    Who has the best PF username?

    how does it soand??? I mean the "ch"!!!
  28. S

    Distinction between experiment and theory

    As you know we use the experimental methods to confirm our theories. so we measure some quantities to have a sense about the errors may occure. In some of these experiments we do not measure the considered quantity but another quantity that later relates to the desired one with ANOTHER THEORY...
  29. S

    Wave and particle.

    Dear selfAdjoint, Marlon, thanks a lot. I think I got it!!!
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